This invention is concerned with tamper-evident closures, and more particularly with improved plastic closures having a 2-tier bridge arrangement in a tamper-evident band.
Plastic closures of the type used on oil containers or beverage containers are commonly provided with a tamper-evident band that breaks away from an upper part of the closure, either partially or completely, as the closure is moved to remove it from the container. For example, when a closure is unthreaded from a bottle, bridges that connect an upper part of the closure to a tamper-evident band constituting a lower part of the closure are designed to break, so as to give an indication that the bottle has been opened.
Most closures of the foregoing type employ a single tier or row of bridges spaced along a circumferential line of weakness, but closures employing a 2-tier bridge arrangement are also known. Those closures usually have axial lines of weakness in addition to upper and lower circumferential lines of weakness in their tamper-evident bands, and the closures are designed so that as they are moved to remove them from containers, a portion of the tamper-evident band between the upper and lower lines of weakness is either broken into separate pieces or tears away as a long strip..
In general, prior tamper-evident closures have bridges that may break prematurely -when the closure is applied to a container. Axial lines of weakness provide other sources of premature breakage. Strong bridges may avoid the problem of premature bridge breakage but tend to make the closure removal operation difficult to perform. Moreover, prior tamper-evident bands are subject to undesirable cocking or tilting during closure removal.